To clarify, I'm not talking about the rules used to clarify legislation after it is passed.

For instance, since the CFAA (Computer Fraud and Abuse Act) has already been signed into law, what is the process a congressperson would go through to have the text of that legislation altered?

My initial thought was that it was just an amendment, but if that is the case, what is the procedural difference between an amendment proposed before the bill leaves the chamber, versus the process of amending an already enacted law?